Wood, 34, was 0-2 with an 8.64 ERA in nine appearances so far this season. In 8 1/3 innings, he had allowed eight runs (all earned) on eight hits and 11 walks with just five strikeouts. Wood signed a one-year deal worth $3 million to stay with the Cubs this season, with a team option for 2013.

Wood gave up a run on a hit and two walks Tuesday against the Cardinals.

Friday morning, Wood's wife posted a message that seemed to confirm the news on her Facebook page, writing: "Every story has an end but in life every ending is just a new beginning."

The fourth overall pick of the 1995 draft and 1998 Rookie of the Year will retire with a career record of 86-75 with a 3.67 ERA and 63 saves. Once a dominant starter, Wood reinvented himself as a reliever after arm troubles.

Wood will always be remembered for his promise as much as his production. In just his fifth career start, a then-20-year-old Wood struck out 20 Houston Astros and allowed just one hit -- an infield single -- and no walks in a game on May 6, 1998. It was prehaps the greatest regular-season pitching performance in the game's history. Besides the infield single to Ricky Guiterrez, the only other batter to reach the base was Craig Biggio, who was hit by a pitch. Wood finished the season 13-6 with a 3.40 ERA, edging Todd Helton in National League Rookie of the Year voting.

However, Wood's problems began the next season when he underwent Tommy John surgery in spring training of 1999, missing the entire season. He returned in 2000 and then returned to form in 2001, going 12-6 with a 3.36 ERA. He had perhaps his best season in 2003, going 14-11 with a 3.20 ERA and a league-leading 266 strikeouts as the Cubs won the NL Central and were famously within five outs of the World Series before losing to the Marlins.

Wood struggled with injuries from 2004 to 2006, making 22 starts in 2004 and just 14 in the next two seasons combined.

In 2007, he returned as a reliever and then recorded 34 saves in 2008. He signed on with the Indians in 2009 to serve as the team's closer and was traded to the Yankees during the 2010 season. He re-signed with the Cubs for the 2011 season and served as the set-up man to Carlos Marmol. He appeared in 55 games in 2011, putting up a 3.35 ERA and striking out 57 batters in 51 innings, while walking just 21.

Wood will finish his career with 1,581 strikeouts after starting his career to become the fastest pitcher to 1,000 career strikeouts in just 134 games and 853 innings pitched.